Multicast exchange optical switch is a wavelength-independent optical device, which splits an input beam into a plurality of output beams and directs them to different output ports. As one of key components in the Reconfigurable Optical Add-Drop Multiplexer (ROADM) system of the next generation, the multicast exchange optical switch is generally used in conjunction with a wavelength selective optical switch to accomplish colorless, directionless and contentionless features for the ROADM system, which are important to increase flexibility and reduce cost of the network construction.
Currently, most commercial available multicast exchange switches are implemented in a splicing form or an integrated form. When the multicast exchange switch is configured with discrete planar lightwave circuit (PLC) splitters and switches spliced together, ports of these splitters and switches need to be interconnected through a number of optical fibers. As the number of ports increases, assembling challenges become much higher and size of the switch becomes larger. Alternatively, the multicast exchange optical switch may be configured as a single monolithic PLC integrated with a plurality of splitters and switches. However, such an integrated configuration is difficult to fabricate, needs special manufacture equipments, and has high power consumption due to control of the PLC switches.